The present invention relates to a method for analyzing a signal waveform containing an oscillatory component and an aperiodic component, a computer program implementing the signal waveform analysis method, a method for analyzing vehicle dynamic characteristics with the signal waveform analysis method, and a computer program implementing the vehicle dynamic characteristic analysis method.
Conventionally, there is a method of analyzing the period of an oscillatory component of such a measured signal as indicative of an acceleration of a machine at acceleration or deceleration when the measured signal contains an oscillatory component and an aperiodic component (or henceforth referred to as “trend component”). One such analysis method includes removing the average or linear regression component of the whole measured signal from the measured signal and performing a Fourier analysis on the processed signal, while another such analysis method includes performing a wavelet analysis directly on the measured signal. FIG. 27 shows an example of signals containing an oscillatory component and a trend component, which is, for example, a vehicle acceleration at acceleration. Such a vehicle acceleration affects vehicle driveability. In order to evaluate such a vehicle acceleration, a signal waveform analysis is performed.
Such a method of analyzing vehicle driveability is disclosed in Japanese Patent No. 2579646 (henceforth referred to as JP2579646). The method disclosed in JP2579646 comprises: finding peaks of oscillation of a vehicle acceleration detected by acceleration detecting means; determining a change from the middle of the range of the oscillation before acceleration to the middle of the range of the oscillation after acceleration; determining the ratio of the amplitude of the oscillation at each peak after acceleration to the determined change of the meddle of the oscillation; and determining a variation of the determined ratio with respect to its regression line as an evaluation value for vehicle drivability.